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NanoFab Tool: Reynolds Tech Silicon Nitride Etch Wet Bench

Photograph of the Reynolds Tech silicon nitride etch wet bench.

The Reynolds Tech silicon nitride etch wet bench uses dilute phosphoric acid to preferentially etch silicon nitride on silicon. The process is used to define silicon nitride islands that mask the oxidation of the silicon during high temperature furnace processing. The bench can accommodate substrates ranging from 200 mm diameter wafers down to small pieces.


  • Two 90 % phosphoric acid dip tanks with lids.
  • Dump rinse with a lid.

Usage Information

Supported Sample Sizes

  • Maximum wafer diameter: 200 mm (8 in).
  • Small pieces supported: Yes.

Typical Applications

  • Furnace oxidation masking.
  • Complementary metal–oxide–semiconductor (CMOS) local oxidation of silicon (LOCOS) processes.
Created June 19, 2014, Updated February 24, 2023